Showing posts from November, 2018

A ebay fake GTX 1050/2GB video card is really a GK107B4 GTX 650ti/1GB: restoring functionality by flashing video BIOS with CH431A board

I (knowingly) purchased a fake GTX1050 from ebay for about $90. That's how you know it's fake, of course. It performed OK for desktop apps but was way slow for any benchmarks and also crashed with corrupted video garbage whenever more than 1GB of RAM was used. Of course eBay gave me my money back, which I was counting on when I made the purchase. 

The back of the board gave no real hints to the actual GPU, though it did expose a video bios flash ram chip. NVFLASH couldn't reprogram it, probably due to intentional corruption of the firmware, so I had to purchase a CH431a programmer (for all of $3 on ebay, plus a clip to connect it while still soldered onto the board!!). Before flashing it I had to decide what it actually was. Taking off the heat sink revealed a model number on the board: gk107b4, which could be just about anything in the GTX 600 series. Interestingly, the chip had some of the writing on it worn off. Like they were trying to head off possible returns. Only this part remained: 220-a.

 I eventually guessed it was a GTX650ti, and using tech powerup's video bios database flashed the card. The first flash didn't work - no video output. But I hadn't been that careful about matching up the outputs - this card had HDMI out, and the bios I downloaded only had MiniHDMI. So I tried again with a perfect match. Bingo: Working video card. I benchmarked using userbenchmark which allowed me to compare video card performance to all the other 650ti's out there. The card benchmarked right in the middle of the pack so either I guessed right, or just close enough.

I also tried a longer benchmark with unigine heaven 4.0. Worked fine, no glitches or otherwise. Success! But it's a damn slow card compared to a GTX 1050. Who falls for this kind of thing, anyway? On the upside, this card performs way better than a rectangular scrap of cardboard that I scrawled GTX 1050 on, and for about the same cost. If you discount my time that is, which is always a mistake :-(.

Replacing video BIOS on fake GTX video cards on ebay

For a 3rd or less of the price of a new video card it's possible to purchase the "same" thing from ebay, also new, with slow boat shipping from china. Sadly, the cards are fake, with real GPUs but much older low-end that what's advertised. 

The fake cards I purchased had been reprogrammed to show different, much fancier GPU names, but also more memory than they really had. Thankfully ebay refunded my money with little fuss. Next question: can the cards be reflashed to their original BIOS? A fake name is no big deal but faking more memory than you really have causes massive issues in games.

Here are the tools I used:

A $3 USB eprom flasher called the CH341A. Software to drive this is here (not sure if it has malware, virus total thinks so, so I used a burner winxp image). 

The general method for using the CH341A to flash nvidia firmware is written up here, with some errors (extra steps, not harmful).

The replacement firmware can be found online in this excellent database, for instance here's all the GTX 550 Ti firmware that could be tried for a 1GB card.

After using the CH43A1it's possible to use a hacked version of nvflash to swap in new firmware without using the finicky hardware. nvflash XYZ.rom -4 -5 -6 

I was able to flash 2 out of 3 cards, but only for 1 card could I find a BIOS that made it work properly. So "success" but not full success. Kind of a lot of time wasted! Later I'll discuss each card in detail and post photos.

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